Telephone instrument



Sept; 27, 1938. D. SSPENS STEUART 2,131,529

TELEPHONE INSTRUMENT Filed Jan. 21, 1936 4 Sheets-Sheet 1 1 I4 1;" m M l6 6 o ifii F Sept. 27, 1938. s. SPENS STEUART 2,131,529

I TELEPHONE INSTRUMENT Filed Jan. 21, 1936 4 Sheets-Sheet 2 Sept. 27, 1938. v D. s. ENs SH'EUART I 2,131,529

.TELEPHONE INSTRUMENT Fild Jan. 21, 1936 4 Sheets-Shet 3 Sept. 27, 1938. D. s. SPENS STEUART 2,131,529

TELEPHONE INSTRUMENT Filed Jan. 21, 1956 4 Sheets-Sheet Patented Sept. 27, 1938 UNlTED STATES PATENT OFFiCE TELEPHONE INSTRUBIEN T Douglas Stuart Spens Steuart, Regents Park,

London, England 1'7 Claims.

The present invention relates to telephone instruments and has as its main object the provision of a telephone set for use on public and private telephone systems which will enable a subscriber using the telephone to write down messages or refer to papers on his desk and generally to use the telephone with a minimum of strain and inconvenience.

According to the main feature of the invention, a telephone set comprises a receiver with limited range which can only be heard by a user having his ear in close proximity thereto, a transmitter arranged to respond to speech produced a considerable distance away, e. g. two feet, and means for supporting the receiver at such a distance from the transmitter and in such a position relative thereto that a user may have the receiver supported within audible range of his ear while leaving a clear space between his mouth and the transmitter for the purpose described. With this arrangement the user has both hands at liberty so that whilst telephoning he can easily write and/or refer to papers Whichcan conveniently be arranged on his desk in front of the mouthpiece and his head can be comfortably maintained in positions convenient for speaking, reading and writing.

The receiver is arranged so that the speech produced thereby can only be heard when the ear of the user is within a short distance, e. g. four inches, from the earpiece, so that the speech is generally audible only to one person in the room. There is preferably provided a member which normally supports the earpiece close to the telephone 5 set but is adjustable so as to support the earpiece at a convenient distanceof up to two feet in front of the set. The movement of this member is preferably arranged to control contacts in the line circuit of the set.

A subsidiary feature of the invention relates to a device for overcoming packing of the carbon granules of the transmitter, said device being operable at a convenient distance from the transmitter so that it may be readily operated by the subscriber to agitate the carbon granules with a minimum of effort.

A further feature of the invention resides in the provision of a transmitter located at the rear of the set and provided with an enlarged mouthpiece extending towards the front of the set and in which a dial switch is also provided at the front of the set.

The invention will be better understood by reference to the following description taken in conjunction with the accompanying drawings comprising Figs. 1-12 in which:

Figs. 1, 2 and 3 show respectively a side elevation (partly in section), a plan view and a front elevation of a telephone desk se Fig. 4 shows a detailed View of an anti-sidetone device,

Fig. 5 shows another view of the anti-side tone device with a Bowden wire attachment,

Fig. 6 shows an alternative anti-side tone device using a pneumatic tube,

Fig. 7 shows an alternative form of telephone desk set in which the dial switch is located in the centre of the opening to the mouthpiece,

Figs. 8 and 9 show an alternative method of holding the earpiece by means of lazy tongs,

Figs. 10, 11 and 12 show a further modified construction of telephone desk set. V

A description will first be given of, the telephone desk set shown in Figs. 1, 2 and 3.

A specially constructed mouthpiece l for collecting and concentrating sound Waves received from a distance is arranged so that alternate cylindrical elements of its internal surface are substantially parallel to the'axis of the mouthpiece 25 and at thereto. It is also provided at its opening with two internalcoaxial partitions which have the same shape as the'corresponding portion of the internal surface of the mouthpiece. These partitions are found to increase the sound concentrating efiect without introducing distortion. For a further description of this type and modified types of mouthpiece reference should be made to my co-pending application, Ser. 'No. 52,255, filed Nov. 29, 1935, Patent No. 2,087,052, 0 issued July 13, 1937.

The mouthpiece is connected by means of .a sound passage 2 to a carbon granuletransmitter 3 which is fitted into a housing 4 of suitable size and shape which is attached to the remote end 40 of a rectangular base plate l2. A dial switch 5 is fitted on the front near end of the base plate below the mouthpiece so that the whole forms a neat, compact and symmetrical desk set. The receiver 6 is attached by means of a stirrup .1 to a telescopic tube forming the inner member of a set of telescopic tubes slidably mounted within an outer member 8 fixed to a rod 9 which is secured through a friction grip member ID to the swivel support I l fitted to the rear of the instrument casing I2.

With the desk set in the condition shown in the drawings, the receiver 6 rests close to the mouthpiece I and the set is disconnected from the line by means of the ebonite pin l3 which is secured to the outermost movable tubes and separates the springs |5 which are inside a portion of the tube shown in section and are secured to the rod 9. The line circuit is held open at contacts l6 and with the receiver in this position the indicating member H is located near the o designation thereby indicating that the set is disconnected. To take the instrument into use the receiver 5 is pulled forward to extend the telescopic tubes. When the outermost movable telescopic tube is extended the ebonite pin I3 is withdrawnfrom the springs |5 thereby allowing the contacts I6 to close and connect the set to the telephone line. The friction member l allows the receiver arm to be raised or lowered to a convenient position against the ear of the user- I Owing to the use of the enlarged mouthpiece I, the user can speak at a distance of up to approximately two feet from the mouthpiece and still be easily heard at the other end of the connection. It is found that about 1 feet from the mouthpiece constitutes the most comfortable distance for dialling and provides convenient room on the desk in front of the telephone set for papers, etc. As the receiver is self-supporting, both hands are free so that the user can easily write and/or refer to papers whilst telephoning with his head comfortably maintained in a convenient position. When the call is finished, the receiver 6 is pushed back into the original position, whereupon the ebonite pin l3 engages the springs |5 thereby opening the line circuit at contacts IS. The outermost telescopic tubes are arranged to telescope more easily than the inner ones so as to avoid any risk of the set being left connected up due to the receiver not being completely pushed back althoughthis is unlikely as the receiver in its forward position is certain to attract attention. If the user prefers to listen with the right car it is only necessary for him to rotate the rod 9 about the swivel support H and bring the receiver 6 forward to the right of the mouthpiece If it is required to. re-dial or re-call the operator, the largest sliding tube only of the telescopic arm need be closed and this operation is rendered more convenient by the provision of the milled collar M which is secured to its near end. An indicator I1 is provided to enable the user to ascertain the position of the switch contacts. I a

To prevent packing of the carbon granules, a press key I8 is provided at the front of the set so that the user by depressing this key causes the carbon granules to be agitated and thus maintains the transmitter IE3 at its maximum efficiency. In response to the depression of the key Hi, the lever which is pivoted at 2| causes the bell-crank lever 22 to rotate in a clockwise direction; the steel pawl 23 engages the pin 24 which is attached to the hammer rod 25 and causes. the rod 25 to move to the right against the action of the spring 26. This movement continues until the pawl 23 has. describedga downward are sufficient to slip from the pin 24. The spring 25 then drives the hammer rod 24 back into its original position, where it strikes the agitator pin 21 with sufficient force to disturb the carbon granules andfleliminate any packingf. The agitator pin 21 is designed to enter a cavity in the transmitter to engage a point behind the rear electrode so that the blow is. delivered at the most suitable point. A further key 29 is provided for operating an anti-side tone device which will be described later with reference to Figs. 4 and 5.

It will be readily understood that the telephone set may be provided with a pair of telescopic arms similar to that shown arranged so that two receivers may be applied simultaneously to the ears; the distance between such receivers is preferably made readily adjustable.

Figs. 4 and 5 show the construction of the antiside tone device arranged to be operated by the key 23 of the telephone set shown in Figs. 1, 2 and 3. When the key 29 is depressed it raises the lever 30 which rotates the bell-crank lever 3| and the lever 32. This latter turns the spindle 33 to which is connected a flexible strip 34. The free end of the flexible strip which is provided with a button preferably of sound-absorbing material is thus brought into contact with the centre of the transmitter diaphragm 35, thereby rendering the transmitter |9 inoperative. It will be appreciated that by means of this construction room noises and side-tone may be completely eliminated at the will of the user by the operation of the key 29 convenientlylocated in front of the instrument. An alternative method of operating the anti-side tone device is shown in Fig. 5 in which a Bowden wire 36 is shown connected to the arm 32. When the finger press 31 is operated, the Bowden wire draws the arm 32 to the right and the free end of the flexible strip 34 is thereby pressed against the centre of the diaphragm 35 in the manner previously described.

With this arrangement the side-tone and room noises may be controlled at any desired distance from the set.

Fig. 6 shows a further alternative method of operating the anti-side tone device. In this construction a metal tube 48 is inserted under the protective grid of the transmitter and is connected by a rubber tube 39 of convenient length to a hollow rubber bulb 38. When the bulb 38 is squeezed the air pressure inflates a small hollow rubberbulb 4| fitted to theother end of the metal tube 40. The bulb 4| is situated near to the centre of the diaphragm35 but does not normally touch it. When it is inflated, however, it presses against the diaphragm and completely prevents the diaphragm responing to oncoming sound-waves.

Fig. 7 shows an alternative form of construction of telephone set in which the dial switch 5 is mounted in the centre of the opening to the mouthpiece and a sound reflecting cone 28' is fit- 'ted behind the dial switch. The sound waves are collected by the annular orifice surrounding the dial switch and are then concentrated and led to the transmitter in the same manner as in the mouthpiece shown in Fig. 1. The receiver is secured to a device for mechanically supporting it close tothe ear, e. g. the telescopic tubing shown in Fig. 2.

Fig. 8 shows the use of lazy tongs 5| for supporting an earpiece 49 close to the ear when using a telephone set of the type described in connection with Figs. 1, 2, 3 and '7. The earpiece 49 is connected by means of a flexible sound tube 48 p to a moving coil receiver 41 which is preferably located in the same casing as the transmitter or adjacent thereto. The earpiece 49 is supported in. a clip 5|! fixed tothe free end of the lazy tongs 5|. When the lazy tongs are closed the rod 52 I presses on a bell-crank lever 53 which holds down the switch rod 43 against the tension of the spiral springs 54. The switch rod 43 in turn holds open the line contacts in the manner shown in Fig. 2. When the lazy tongs are extended the bell-crank lever is rotated by the r set of telescopic tubes of spring 54, thus allowing the spring 55 to raise the switch rod 43 to cause the switch contacts to close in the manner described in connection with Fig. 2. Alternatively, the earpiece may be taken from the clip 58 and moved to and from the ear without necessitating the extension of the lazy tongs. When the earpiece is taken from the clip the spring 56 causes the rod 52 to move forward away from the bell-crank lever 53 thereby causing the line contacts to operate in the manner previously described. Alternatively, the receiver itself may be fitted to the lazy tongs without the use of the sound tube. It will also be understood that the lazy tongs arrangement may be replaced by a the type shown in Fig. 2. The moving coil receiver with a diaphragm of the shape shown is very sensitive so that the speech produced thereby may be heard at a distance of up to approximately four inches from the earpiece. It will be appreciated that by 10- cating the receiver inside the casing of the set it is protected from damage and may therefore be made more sensitive than if it had to withstand mechanical shocks.

A further modified construction is shown in Figs. 10, 11 and 12. In this arrangement the mouthpiece la is similar in many respects to that shown in Fig. 7 but is additionally provided with conical surfaced members 66, 60a arranged coaxial with the mouthpiece and serving to assist in the reflection and concentration of the sound. A fuller description of this feature is also contained in my copending application.

The mouthpiece I has fitted centrally within its orifice an automatic dial 6! held in position by means of the cylindrical mounting extension 62 of the outermost conical member 60. The inner end of the mouthpiece is connected to a carbon granule transmitter 53 and is fixed to a base 55 by means of a bracket 65.

A rounded housing 65 is fitted over the microphone and the associated mechanism to form a neat and protected construction. The dial connections are carried through the mouthpiece by means of an insulated tube 57 to a terminal block.

The mouthpiece is provided with a suitable dustprotecting screen or the like while the receiver 58 is carried by a telescopic arm 59 of similar construction to that previouslydescribed with reference to Figs. 1, 2 and 3.

The mechanism for agitating the carbon granules of the microphone is similar to that previously described but is in this instance operated by means of a push rod 10 passing through the mouthpiece la. The instrument is mounted upon a bell box H which is itself mounted upon a turntable 72. The turntable i2 is carried by a ball race '53 upon a rubber pad M while a clamping member #5 moved by means of the cam 15 is adapted to secure the instrument in any desired position. The cam 16 is carried by a shaft 7? provided at either end with operating handles 18.

The telescopic arm 69 carrying the receiver 58 is attached to rod 79 by means of a taper fricticn clutch which is capable of being locked in the desired position by a locking nut 86. As in the previous embodiment the receiver is adapted to be transferred from one side of the instrument to the other as desired.

Although various forms of construction have been described, it will be understood that these are given only by way of example and that various modifications and additions may be made with out departing from the invention. a

I claim: 1. A telephone sub-set assembly comprising in combination a base, a microphone mounted in close proximity to said base, a short enlarged mouthpiece immediately in front of and co-axial with said microphone and directed in a certain direction away from said base, said mouthpiece being constructed so as to enable sounds uttered at a distance of 10 to 20 inches away from and in front of the open end to generate speech currents of normal strength'with a minimum of distortion, a receiver, an extendible and collapsible support for said receiver secured at one end to said base in close proximity to said microphone and normally supporting said receiver alongside said microphone to form a compact unit when not in use and extendible to a distance of 12 to 24 inches in a direction parallel with the axial direction of said microphone and mouthpiece whereby the person using the instrument may be allowed the free use of both hands and provided with an unrestricted space of 10 to 20 inches between his mouth and the instrument thereby allowing View and access to a desk and at the same time permitting the location of receiver sufiiciently close to his ear to ensure that the incoming speech sounds are heard exclusively by him.

2. A telephone sub-set assembly comprising in combination a base, a microphone mounted in close proximity to said base, a short enlarged mouthpiece immediately in front of and co-axial with said microphone and directed in a certain direction away from said base, said mouthpiece being constructed so as to enable sounds uttered at a distance of 10 to 20 inches away from and in front of the open end to generate speech currents of normal strength with a minimum of distortion, a receiver, an extendible and collapsible support for said receiver secured at one end to said base at a point located substantially on the axial line of said microphone and mouthpiece and normally supporting said receiver alongside said microphone to form a compact unit when not in use and extendible to a distance of 12 to 24 inches in a direction parallel with the axial direction of said microphone and mouthpiece whereby the person using the instrument may be allowed the free use of both hands and provided with an unrestricted space of 10 to 20 inches between his mouth and the instrument thereby allowing View and access to a desk and at the same time permitting the location of receiver sufiiciently close to his ear to ensure that the incoming speech sounds are heard exclusively by him.

3. A telephone sub-set assembly comprising in combination a base, a microphone mounted upon and in close proximity to said base, a housing mounted upon said base and surrounding said microphone, an enlarged mouthpiece immediately in front of and co-axial with said microphone and projecting outwardly from said housing, a

receiver, and an extendible and collapsible support for said receiver secured at one end to said receiver and at its other end to said base im m-ediately behind said microphone and said hous' ing, said support normally holding said receiver 1 immediately alongside said mouthpiece and housing to form a compact unit when not in use and extendible to a distance of 12 to 24 inches in a direction parallel to the axial direction of said mouthpiece and microphone.

i. A telephone sub-set assembly comprising in combination a base, a microphone secured to said base at a fixed angle and directed away from said base, a housing surrounding said microphone and secured to said base, an enlarged mouthpiece in front of and co-axial with said microphone permitting generation of normal intensity speech currents by said microphone by speech uttered at 10 to 20 inches distant from its open end, and an automatic dial switch located within the open end of said mouthpiece.

5. A telephone sub-set assembly comprising in combination a hollow base containing bell mechanism, a microphone secured to the upper surface of said hollow base, an enlarged mouthpiece secured in front of and co-axial with said microphone, a receiver, and extendible supporting means secured at one end to said receiver and at the other end to said upper surface of said hollow base.

6. A telephone sub-set assembly comprising in combination a base, a microphone secured directly to said base in close proximity thereto, an enlarged mouthpiece in front of and axially aligned with said microphone and directed at a fixed angle away from said base, a receiver and a telescopic support arm for said receiver secured at one end to said base by means permitting adjustment of the vertical angle of said telescopic support and also the movement bodily of said telescopic arm and said receiver from one side of the microphone to the other.

'1. A telephone sub-set assembly comprising in combination a base member for sup-porting the whole assembly without securing means upon a horizontal surface, a microphone secured upon the upper surface of said base member, an enlarged mouthpiece in front of and co-axial with said microphone and arranged with its open end directed in an upwardly inclined direction away from said base member, a receiver and extendible means for supporting said receiver at a distance from said base member and microphone in a direction substantially the same as that of the open end of the mouthpiece, said supporting means being secured to said base at a point immediately behind said microphone so that said extendible means may be arranged to locate the receiver carried thereby at any point along a path close to and parallel with the direction of the open end of said mouthpiece and allows of the compact location of the receiver close alongside the microphone and mouthpiece in the out of use position of the instrument.

8. A telephone sub-set assembly comprising in combination a base member, a microphone secured to the uppersurface of said base member, an enlarged mouthpiece for extending the sound response distance of said microphone said mouthpiece having its open end directed in an upwardly inclined direction away from said base, a receiver and an extendible and collapsible supporting means secured at one end to said base member at a point behind said mouthpiece and substantially in alignment with the direction of the open end of the mouthpiece so as to enable the receiver to be located at any point along a path adjacent to and parallel with the said mouthpiece direction up to a distance within the extended response distance of said microphone.

9. A telephone sub-set assembly comprising a base, a microphone secured thereon with its axial and major sound response direction upwardly inclined away from said base, a mouthpiece having an enlarged open frontal end arranged in' front of and co-axial with said axial direction of said microphone, a receiver, a telescopic tubular support arm secured at one end to an upward extension of said base at a point immediately behind said microphone and substantially upon the said axial direction thereof when produced rearwardly and gimbal means for carrying said receiver upon the outer end of said telescopic tubular support.

10. A telephone sub-set assembly as claimed in 7 claim 9 in which the support arm is secured to said upward extension of the base by means of a friction grip permitting rotation about a horizontal axis and in which the upward extension is formed as a swivel support rotatable about a vertical axis.

11. A telephone sub-set assembly comprising in combination a base plate, a microphone having its major sound response axis directed in an upwardly inclined direction away from the base, an enlarged mouthpiece in front of and co-axial with said microphone axis, a receiver, an extendible support arm consisting of an outer tubular member connected at one end to said base at a point immediately behind said microphone, and a plurality of nested movable tubes disposed within said outer tubular member, a circuit making and breaking device carried by said outer tubular member, the outermost of said nested movable tubes having means for operating said circuit making and breaking device by sliding movement within said outer tubular member so as to cause the disconnection of the instrument from the line when said outermost movable tube is in its fully nested position and the innermost nested tube being connected by a hinged stirrup member to the said receiver.

12. A telephone sub-set assembly as claimed in claim 11, in which the outermost nested movable tube is provided with a manual grip member whereby the said nested member may be moved to control the line switching directly and not through the intermediary of the other nested members.

13. A sub-set assembly for use in automatic telephone systems comprising a base plate, a microphone secured to said base plate, an enlarged sound collecting mouthpiece in front of said microphone for increasing the response distance thereof, a dial switch located in the enlarged open end of said mouthpiece and a sound reflecting member disposed immediately behind said dial switch within the mouthpiece.

14. A telephone sub-set assembly comprising in combination a base, a microphone mounted in close proximity to said base, a mouthpiece amplifier for said microphone having a passage therethrough with alternate surface portions thereof disposed parallel to the direction of said passage and inclined at 45 thereto for collecting sounds at its open end and transmitting them in intensified form with the minimum of distortion to the transmitter so as to enable sounds uttered at a distance of 10 to- 20" away from and in front of the open end to generate speech currents of normal strength with a minimum of distortion, a receiver, an extendible and collapsible support for said receiver secured at one end to said base in close proximity to said microphone and normally supporting said receiver alongside said microphone to form a compact unit when not in use and extendible to a distance of 12 to 24 inches in a direction parallel with the axial direction of said microphone and mouthpiece whereby the person using the instrument may be allowed the free use of both hands and provided with an unrestricted space of 10 to 20 inches between his mouth and the instrument thereby allowing view and access to a desk and at the same time permitting the location of receiver suiiiciently close to his ear to ensure that the incoming speech sounds are heard exclusively by him.

15. A telephone sub-set assembly comprising in combination a base, a microphone secured to said base at a fixed angle and directed away from said base, a housing surrounding said microphone and secured to said base, an enlarged mouthpiece amplifier for said transmitter having a partitioned passage therethrough the surfacesof which passage and of the partitions of said passage being all parallel to the axis of the mouthpiece or inclined at 45 thereto for collecting sounds at its open end and transmitting them in intensified form with the minimum of distortion to the transmitter for permitting generation of normal intensity speech currents by said microphone to speech uttered at 10 to 20 inches distant from its open end and an automatic dial switch located within the open end of said mouthpiece.

16. A telephone sub-set assembly comprising in combination a base, a microphone secured directly to said base in close proximity thereto, a mouthpiece amplifier in front of and axially aligned with said microphone and directed at a fixed angle away from said base, said amplifier having a passage with the surfaces of alternate portions thereof parallel to its axis and inclined at 45 thereto and internally disposed surfaces inclined at 45 to the axis, a receiver and a telescopic support arm for said receiversecured telescopic arm and said receiver from one side of the microphone to the other.

17. A telephone sub-set assembly comprising in combination a base member, a microphone secured to the upper surface of said base member, an enlarged mouthpiece amplifierfor extending the sound response distance of said microphone, said mouthpiece having its open end directed in an upwardly inclined direction away from said base and having a partitioned passage therethrough the surfaces of which passage and of the partitions therein being all parallel to the axis of the mouthpiece or inclined at 45 thereto with internally disposed members locatedcentrally in said passage and having surfaces inclined at 45 to said axis, a receiver and an extendible and collapsible supporting means secured at one end to said base member at a point behind said mouthpiece and substantially in alignment with the direction of the open end of the mouthpiece so as to enable the receiver to be located at any point along a path adjacent to and parallel .with the said mouthpiece direction up to a distance within the extended response distance of said microphone.

DQUGLAS- STUART SPENS STEUART. 

